Connect to Greenplum Data in Ruby

The CData ODBC Driver for Greenplum makes it easy to integrate connectivity to live Greenplum data in Ruby. This article shows how to create a simple Ruby app that connects to Greenplum data, executes a query, and displays the results.

Create an ODBC Connection to Greenplum Data

If you have not already, first specify connection properties in an ODBC DSN (data source name). This is the last step of the driver installation. You can use the Microsoft ODBC Data Source Administrator to create and configure ODBC DSNs.

To connect to Greenplum, set the Server, Port (the default port is 5432), and Database connection properties and set the User and Password you wish to use to authenticate to the server. If the Database property is not specified, the default database for the authenticate user is used.

Installing Ruby and Necessary Gems

If you do not have Ruby installed, refer to the Ruby installation page. With Ruby installed, you will need to install the ruby-dbi, dbd-odbc, and ruby-odbc gems:

gem install dbi
gem install dbd-odbc
gem install ruby-odbc

Create a Ruby App with Connectivity to Greenplum Data

Create a new Ruby file (for example: GreenplumSelect.rb) and open it in a text editor. Copy the following code into your file:

#connect to the DSN
require 'dbi'
cnxn = DBI.connect('DBI:ODBC:CData Greenplum Source','','')

#execute a SELECT query and store the result set
resultSet = cnxn.execute("SELECT Freight, ShipName FROM Orders WHERE ShipCountry = USA")

#display the names of the columns
resultSet.column_names.each do |name|
 print name, "\t"
end
puts

#display the results
while row = resultSet.fetch do
 (0..resultSet.column_names.size - 1).each do |n|
 print row[n], "\t"
 end
 puts
end
resultSet.finish

#close the connection
cnxn.disconnect if cnxn

With the file completed, you are ready to display your Greenplum data with Ruby. To do so, simply run your file from the command line:

ruby GreenplumSelect.rb

Writing SQL-92 queries to Greenplum allows you to quickly and easily incorporate Greenplum data into your own Ruby applications. Download a free trial today!